Conditioning polymers meant for deposition onto negatively charged surfaces, such as fabric, skin, or hair, are included in many common consumer product compositions. Such products can provide consumer-desired benefits such as softness, lubricity, hand, anti-wrinkle, hair conditioning, frizz control, skin miniaturization, and color protection. Difficulties frequently arise in achieving effective conditioning agent deposition onto these surfaces, especially when the conditioning agent is delivered in the form of rinse-off compositions, such as hair shampoos, body washes, detergents, and fabric softeners, as well as other surface cleansing and surface treatment products.
Various quaternized aminosilicone polymers have been proposed for use as conditioning polymers. The effectiveness of any particular conditioning polymer depends not only upon the chemical and physical properties of the conditioning polymer itself, but also upon those of the targeted surface, as well as various other materials that may be included in the composition. Thus, a conditioning polymer delivering exemplary performance under one set of conditions may provide little or no advantage in another. In order to ensure desired performance, the conditioning polymer should possess properties that complement those of the particular targeted surface and consumer product formulation.
Varying structural parameters, such as molecular weight, cationic charge, hydrophobic substitution, and/or hydrophilic substitution, such as degree of ethoxylation, can significantly impact performance of cationic conditioning polymers. Adjusting these parameters provides a way to modify and control performance aspects of these polymers on a substrate. Further, in order to obtain optimal conditioning benefits, the silicone polymer must be functionalized to favorably interact with the particular substrate to which it will be applied. In addition, the silicone polymer must be able to be formulated into a stable composition that provides the desired level of shelf-stability.
The quaternized aminosilicone polymers must be formulated into consumer-acceptable products. Consumer products such as those in the areas of fabric care, beauty care, pet care, and home care, are most typically aqueous-based products. Aqueous product formulations can be facilitated, for example, by incorporating hydrophilic moieties such as ethoxylate, propoxylate, and more generally alkoxylate moieties into the polymer itself. Alternately, the hydrophobic polymers can be emulsified into the aqueous based products.
Unfortunately, incorporating benefit agents into aqueous based products, especially benefit agents which are hydrophobic and/or surfactant-soluble and/or hydrophilically modified, often results in the benefit agent being preferentially rinsed away from the intended site of deposition, rather than being deposited. The loss of the hydrophobic benefit agents can be particularly pronounced in dilute systems.
Without being bound by theory, the loss of hydrophobic benefit agents can result from the cationic charge being distributed too randomly along the length of the benefit agent polymer. In many cases, the charge is too highly dispersed to adequately facilitate surface deposition.
A further problem occurs in the formulation of quaternized aminosilicone polymers in the context of cleansing compositions (e.g., shampoos), a great number of which (e.g., shampoos, bar soap, and skin cleansing compositions) contain anionic surfactants. Deposition of anionic or nonionic actives onto anionic surfaces from compositions containing anionic surfactants can be especially problematic. Various compositions comprising cationic polymers (e.g., quaternized amines) have been proposed as conditioning polymers in such compositions, however they may not be wholly satisfactory as commercial products.
Without being bound by theory, anionic surfactants can interfere with deposition of actives, including cationic actives, by adsorbing on all surfaces as well as forming complexes/precipitates with the cationic conditioning polymers before the actives can deposit on the targeted surface. Even if deposition occurs, the formulations may exhibit poor stability due to flocculation and precipitation. However, the higher the concentration of anionic surfactant, the more difficult it is to attain active deposition. Among other disadvantages, this leads to non-cost-effective use and waste of materials.
Several cationic conditioning polymer materials exist in the art, but are not wholly satisfactory. There is still a need to provide silicone polymers that are suitable for use in a wide range of consumer product applications. Applicant is not aware of any prior silicone polymer that meets all the desired versatility, shelf-stability, and performance criteria desired in a consumer product context.
For example, the quaternized aminosilicone polymer material described by Ono (WO 99/32539) comprises end groups having heteroatoms such as oxygen, nitrogen, or sulfur, or halogens. These functionalized end groups can lead to undesirable reactions that pose stability issues for compositions comprising these materials. For instance, Ono's silicones can react further through these end groups, leading to further condensation/polymerization of the silicones in the compositions during storage.
Also known in the art are quaternized silicones that include alkylene oxide units, such as U.S. Pat. No. 6,903,061 to Masschelein. The quaternized silicones described by Masschelein tend to be too water soluble, and thus have a reduced capacity as conditioning polymers, since these materials tend to partition into water at a higher than desired level. Further, these materials may have an undesirable feel because of their high permeability to water and water vapor. Further, because of their water solubility, these materials can be difficult to formulate reproducibly. Further, Masschelein discloses materials having only one quaternized nitrogenous group per side of the molecule. This can limit the desired degree of functionality in a silicone material. It would desirable to have a material the provides greater flexibility via the level of quaternization. Similarly, the ethoxylated quaternized silicone materials disclosed by Boutique in U.S. Pat. No. 6,833,344, suffer from many of the same inadequacies of those described by Masschelein.
Unfortunately, such care agents are incompatible with a variety of other consumer product ingredients, not stable over long-term storage, and/or do not deposit well-enough onto the target surface, necessitating their inclusion at levels higher than would otherwise be required if they deposited more efficiently.
Accordingly, it is an object of the present invention to provide consumer product compositions comprising conditioning polymers that can effectively deposit and provide conditioning benefits to substrates while avoiding the aforementioned disadvantages.